Exothermic reaction charge



April 23, 1946. c. A. CADWELL EXOTHERMIC REACTION CHARGE I INVENTOR.CHARLES A. CADWELL BY M, 6

+19 ATTORNEYS ad/ Patented Apr. 23, 1946 Charles A. Cadwell,ClevelandQOhio, assignor to. The Electric Railway Improvement Company,Cleveland, Ohio, a corporation of Ohio Original application January 13,1941, Serial No.

374,229. Divided and this application Novem- "her 30, 1942, Serial N0.467,340

3 Claims. (Cl. 75-457) In the use of exothermic reaction mixtures, andparticularly in the use of mixtures such as are employed in the wellknown alumino-thermic reaction to produce molten metal, one of theproblems encountered is the proper disposition of J the charge in thecrucible. For example, where it is desired to produce molten copper bysuch reaction, the charge may comprise aluminum powder admixed-withcopper oxide in addition to other minor ingredients. It is alsonecessary to provide an ignition powder on the'upper or exposed surfaceof the charge whereby the latter may be readily set on. Once started, ofcourse, the alumino-therrhic reaction is quite rapid and 'may evenbecome violent due to the large amount of heat given off.

However thoroughly the ingredients of the charge are intermixedpreviously toplacein'ent in the crucible, I have found there isa'tendency for such ingredients to segregate, when simply poured intothe latter, due to differences in shape and specific gravity of theparticles, and unless this be controlled, the charge will not fireuniformly. This is particularly objectionable in the case of a smallcharge, as required For this and analogous uses of the aluminothermicreaction, I have found it desirable as 'set forth in my prior Patent No.2,229,045, dated January 21,1941, to utilize an alumino-thermic reactionmixture in which instead of powdered aluminum a powderedcopper-aluminumalloy is employed, the effect of which is to reduce theviolence .of the reaction when the chargeis ignited. Also, as setforthin said 'priorpatent, the charge is desirably madeup'in package orcartridge form so that the precise amount required for a particularoperation may be deposited in the crucible which forms anassociated partof the mold employed bonding operation. Even where, as prescribed, such.car.- tridge, following removal of the. cap whichcloses one end, isquickly inverted into the crucible and thenwithdrawn, a certain amountof segregation is apt to occur, with the result that when ignited thecharge may not react uniformly or in its entirety. I 1 y,

The object of thepresent invention, accord.- ingly, is to provide an.improved method of charging a crucible with material for producingmolten metal by exothermic reactionwhereby such-material will bedeposited in the crucible in a condition which will conduce to a uniformand complete reaction. At the same time the convenience of having amaterial available in packagefor cartridge form is retained. v I I Tothe accomplishment of the foregoing and related objects, the invention,then, consists of the steps hereinafter fully described and particularlypointed out in the claims. p The annexed drawing and the followingdescription set forth in detail certain steps embodying the invention,such disclosed stepsl con- 'stituting, howe'ver, but, one of variousways in which the principle of the invention may be use d. H g

In said annexed drawing: r Fig. 1 is a transverse sectional view of anapparatus for rail'bonding, such apparatus includ ing a mold andassociated crucible for, the production of molten metal by exothermicreaction; Fig. 2 is a perspective view ofa cartridge used in packagingthe charge; v

Fig. 3 is a central section of such cartridge showing disposition of itscontents;

Fig. .4 is an elevational view of a crucible adapted for use in myimproved method, such crucible beingdesigned for pouring the resultantmolten metal instead of discharging the same directly into an associatedmold; and V Fig. 5 is a transverse section of such pouring crucible, theplane of the section being indicated by the line 5 -5, Fig. 4. g

Referring to the rail bonding apparatus illustrated in Fig. 1, this willbe seen to comprise a suitable frame] (shown only in part) which is Iadapted to rest upon ,the top of the rail head 2 ,andsupporta graphitemold block 3. The lower ".portion ofrsuch block is desirably encased ina close fittingmetal shell l through which passes a pin. 5 whereby theblockis pivotally mounted in a clevis 6. "Such clevis is in turnsupported in frame I by means of a bolt 1 which passes through a boss 8on such frame, and a leaf Spring 9 is, attachedto the frame by the samebolting jmeans and is interposed between said clevis and mold toresiliently bear upon the face of the mold opposite its rail-engagingface. It will be understood that frame I includes clamping means whichengage with the rail head and re tain the frame against transversemovement relatively to such head, so that the result of the action ofsaid spring 9 is to retain the mold block closejfi tting contact withthe rail head, e mold block which is of refractory material; preferablygraphite, has a mold cavity l9 connected byway ofa sprue passage 20 withthe self-positioned in the bottom of the crucible,

Attached to the top of the vblock 3 in which crucible 2| is thusprovided, is a cover 23, such attachment being preferablybymeansof ahinge 24 so that the cover may beatilted clearfiof the' crucible when itis desired to have access 'to the latter. Such cover arches upwardlyoverthe crucible and is provided with-a-ventaopening25 centrally thereof,and so coaxial with the cruelble, and this opening is in turn surroundedby an upwardly extending slightly flared rim 26.

Rim26 on the'crucible cover-is designed to receive-and ensure properplacement of a cartridge 21 in which the charge of reaction materials ispackaged. As better shown in:Figs. 2 and 3, this cartridge comprises acylindrical container, e. g. of cardboard, permanently closed-at one endas by a cap 28 and having aremovable cap 29 at its other end. In fillingsuch-cartridge the re quired amount of .igniting powder .30 is firstplacedtherein and vthen the cartridge is filled 9 withthe main. body .3IV of the'charge, such as the previously describedlmixture of comminutedcopper oxide'and copper-aluminum-alloy. in proper proportions. Inutilizing the cartridge 21.just described, to charge the crucible in theapparatus illustrated in Fig. l, theCap 29is removed and the cartridgeis placed in an. inverted, position in the upper rimmed portion of thecover 23, as illustrated in dotted. outline in Fig. 1. The open end ofthe cartridgeis thus seated directly over the central opening 25 whichcommunicates through the. cover withthe interior of the crucible.v

As a result the contents of the cartridge will be centrallydischarged'in the form of a'cylindrical stream against the bottom of thecruciblecharnbeer and then pileup and expand against the crucible wallby a shearing and rolling action of the particles which producesafilling with the finer parti'cles and dust predominating alongthe;

axis of the crucible and the coarser-particles against the wall.,The'upper surface of the chargefl32, as thus placed in the crucible.willbe slightly mounded, as shown in Fig. l.

The ignition powder, originally in ,the bottom, of the cartridgewill nowbe, on top of the, .charge' in the crucible, properly disposedto beignited. This maybe doneb dropping a match through theopening 25following.remova1 of the empty cartridge or by means of a spark gundischarged through such opening.

Upon ignition, the center of the fiery crater accompanying the reactionfollows down the center column of finer particles whichreact more slowlythan the coarser grains and by so doing ive thelatter time to roll intothe fire, all to the end that uponcompletion of thereaction when thebreak through takes place, the .metal is discharged as a hot shot ratherthan as a stream which may under the most adverse circumstances beatricklingstream. s

It is readily seen thatchargingthe crucible by pouring of the cont'e'ntsfrom an obliquelposition of the cartridgemay result in areaction craterthat descends along a tortuous-path, perhaps --reaction of thechargewillmelt thegate 22 instantly upon coming in contact therewith, and

dropping downwardly through sprue opening 20 will-collectdn the moldcavity IS in which the terminal portion 32 of the bond which is to be'weldedrto therail head 2 is held in proper positionby means ofgripperfingers 33. The result is that-the-strands composing the bond terminal-are--more,or;:le ss interfused into a solid molded bond:head which isattached to the rail with a high degree of permanence.

In the modified construction illustrated in Figs. 4 and'5, the crucible34 is provided with a pouringlip 35 instead of ,with asprue opening, anda handle 36 is attached thereto b means of a clamping ring 31. Thcharging cover '38,which is-similar in-form with thatpreviouslydescribed,

-i .hinged.to the crucibleon-the side toward-the handle and aspringcatch 39 isprovided on the latter to engage and retaintnecover in openpositionwhen pouring molten metal from the crucible. ThisfOrm ofcrucible i particularly adapted for use in the production of.relativelylarge charges. of molten metal producedv b exothermicreaction, themetal then being poured into one or more molds inconventional manner.

The various features .of construction which.

characterize 'my. improved crucible, of which several forms are hereinillustrated and "described, forms the subject matter of myico-pendingapplication filed January 13, 1941,. Serial .No. 374,229, out. of whichthe present:applicationhas been divided.

Other modesofapplyingthe principle of my invention may be employedinstead of the one explained, change being made asregards the methodherein disclosed, provided the step or steps stated .by any ofjthe.followin claims or-the equivalentpf such stated step or steps beemployed. g

,I therefore particularly. point outand distinctly claim as myinvention:

1. In a method of charging a crucible..;with material .for producingmolten metal .by vexothermic reaction, such material comprising amixture of. ingredients comminuted .to different degrees of I fineness,the steps which .consist in permitting a measuredbody. ofsuch materialtoflow freely by gravity through an openingrestrictedin area relatively.to. thecross section-of such, crucible .and located. approximatelycentrally over such-crucible, whereby suchjmaterialis deposited in theform of a symmet1 'ical,, 'mounded mass wherein the componentingredients are. distributed uniformly in successive descending planesand then similarly placing on the mounded topof such body a smallerbody.of ignition powder. 1 r

2. In a'method of chargin a crucible with material for producing moltenmetal by exothermic reaction, such material. comprising amixture ofingredients comminuted to dillerent [degrees .of fineness, the stepswhicheonsistin .pouring 'a measured body of; suchmaterial. into suchcrucible -from, above. .and ;restricting the flow oilsirch body where itenters the-crucible :to. a n areasubrespect to the latter, whereby suchmaterial is deposited in the form of a symmetrical, mounded mass whereinthe component ingredients are distributed uniformly in successivedescending planes.

3. In a. method of charging a crucible with ma terial for producingmolten metal by exothermic reaction, such material comprising a mixtureof ingredients comminuted to different degrees of fineness, the stepswhich consist in pouring a measured body of such material into suchcrucible from above, and restricting the flow of such distributeduniformly in successive descending planes, and then similarlydischarging on the mounded top of such body a smaller body of ig- 10nition powder.

CHARLES A. CIADWELL.

